Am I looking at incipient case head separation ?

[fightthenoise]

I’ve never fired a batch of brass enough to wear it out so I just want to confirm what I’m looking at. This brass has always been neck sized. Less than five firings. What do y’all think?

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[ShadeTree]

Unless it doesn't go all the way around and is a partial spot in the chamber causing a thin scratch, it looks like most definitely separation. About the right spot and a thin bright line. Take a paper clip or a stiff piece of small diameter wire and bend a small 90 degree hook in it. Drag it inside back and forth slowly over the area your looking at, you should be able to feel a very small catch or jump as it goes over that internal depression inside the case.

Odd to me that you're saying you neck sized these cases...…...and in less than 5 firings you get this?? The very first firing set up with too much headspace can severely stretch and stress the brass below the web. Do you know how to check headspace?

 

[fightthenoise]

The rifle is a stock Winchester Model 70 in .280 Rem. I haven’t bumped the shoulder and only full sized them for the first firing. I don’t keep strict record of how many firings the bass has so <5 is an educated guess. It’s absolutely in the single digits. The mark goes all the way around. I have never checked head space but I take it need to buy some gauges?

I rubbed a dental pick on the inside of the case and didn’t feel anything so that part has me confused as well.


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[Dwh7271]

Just for grins I’d do the paper clip on the chamber also. It just seems those lines are very uniform in their location.
I agree that it looks like separation but might as well see if there’s something with the chamber too.

 

[ShadeTree]

The rifle is a stock Winchester Model 70 in .280 Rem. I haven’t bumped the shoulder and only full sized them for the first firing. I don’t keep strict record of how many firings the bass has so <5 is an educated guess. It’s absolutely in the single digits. The mark goes all the way around. I have never checked head space but I take it need to buy some gauges?

I rubbed a dental pick on the inside of the case and didn’t feel anything so that part has me confused as well.


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No you don't need to spend any money. Take a factory loaded 280 cartridge (that will ensure the case is within spec length to the shoulder) take a piece of scotch tape and measure the thickness with a caliper. The more yellow masking tape kind usually measures about .004, the more clear or white plastic looking kind around .002, but measure so you know.

Put a piece on the head of the case and trim it all the way around even with the outside edge of case head. Chamber the round, outside. On a .004 piece it would be nice if the bolt meets heavy resistance before you can can completely close the bolt, then stop, don't force it closed, you're good. If the bolt closes normaly add another piece of tape. The bolt should for sure stop before closing with 2 pieces.


Over 1 but not able to close on two .004 pieces, the gun is still safe but brass would stretch like a bugger on the first firing.

Then check a freshly full length sized case from your die, the same way. It could be a factory shell is within .004 in your chamber, but full length sizing with your die puts it to .006 or so. (Really this is the measurement that matters since your reloading.)

Anymore I check EVERY used gun I get before I fire it just so I know what I'm dealing with before I load for it. Got one I have to form a false shoulder for to headspace off of for the first firing.

 

[fightthenoise]

Just for grins I’d do the paper clip on the chamber also. It just seems those lines are very uniform in their location.
I agree that it looks like separation but might as well see if there’s something with the chamber too.

Yeah it’s in the identical spot on every case that has it. No other case has the mark in a different place.


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[TackDriver284]

Are you getting those rings after the first firing?

 

[ShadeTree]

Fightthenoise, I for sure wouldn't shoot those cases again anyway until you figure out for sure what it is, I'd sacrifice one of those cases and take a Dremel and cut a section out across that bright line. If it's from thinning, you will have no problem seeing the thinned section on that line in the inside of the case.

 

[jimbires]

it looks like " the mark " for a case head separation , but it looks to be to high up on the case from what I've seen . I also don't understand this with it being neck sized only . here is a thread I have a few pics in .you'll see it's the same shiny mark , but I'm much lower .


viewtopic.php?f=4&t=35285

 

[gbflyer]

Head separation would not be that uniform. Plus you’d only have excess headspace on the first firing if you’re just neck sizing. It’s a ring in the chamber where the reamer caught a chip. If the primer pockets aren’t loose, ride on.

 

[fightthenoise]

The rifle is a stock Winchester Model 70 in .280 Rem. I haven’t bumped the shoulder and only full sized them for the first firing. I don’t keep strict record of how many firings the bass has so <5 is an educated guess. It’s absolutely in the single digits. The mark goes all the way around. I have never checked head space but I take it need to buy some gauges?

I rubbed a dental pick on the inside of the case and didn’t feel anything so that part has me confused as well.


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Over 1 but not able to close on two .004 pieces, the gun is still safe but brass would stretch like a bugger on the first firing.

Then check a freshly full length sized case from your die, the same way. It could be a factory shell is within .004 in your chamber, but full length sizing with your die puts it to .006 or so. (Really this is the measurement that matters since your reloading.)

This is cool. So I put a piece of masking tape that measures 0.005” on the case head. I cut out a .308 caliber circle with a spare 30-06 case and used that as my circle, so it doesn’t go all the way to the edge of the case head but it covers most of it. Bolt closed fine. Added a piece. Still closed. Added another and it was quite a stiff closing. I peeled the stack of tape off and measured it again and it was 0.013”.

I was worried about masking tape being compressible so I reran the experiment with clear packing tape that measured 0.003”. After two layers it was a little stiffer but not bad. After three layers the bolt was very stiff, but I could have forced it closed. That stack measured 0.0115” after I peeled it off.

My dental pick is too awkward to feel the chamber and I can’t for the life of me find a paper clip but that’s next on my troubleshooting list.



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[fightthenoise]

I’m going to size a fresh batch of cases and see if the ring appears on the first firing. The reamer catching a chip sounds very probable. There is not a case that has this mark anywhere but in this exact spot. I might dissect a case tomorrow and see what the inside looks like. Is this something that could be polished out of the chamber?


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[gbflyer]

I’m going to size a fresh batch of cases and see if the ring appears on the first firing. The reamer catching a chip sounds very probable. There is not a case that has this mark anywhere but in this exact spot. I might dissect a case tomorrow and see what the inside looks like. Is this something that could be polished out of the chamber?


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Yes, it could be polished out on a lathe with some 320 grit and some diesel fuel. I wouldn’t sweat it if it’s shooting well though.

You may see it on the first firing, you may not. It could take 2-3 to get the case to form against it that close to the case head.

 

[ShadeTree]

The rifle is a stock Winchester Model 70 in .280 Rem. I haven’t bumped the shoulder and only full sized them for the first firing. I don’t keep strict record of how many firings the bass has so <5 is an educated guess. It’s absolutely in the single digits. The mark goes all the way around. I have never checked head space but I take it need to buy some gauges?

I rubbed a dental pick on the inside of the case and didn’t feel anything so that part has me confused as well.


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Over 1 but not able to close on two .004 pieces, the gun is still safe but brass would stretch like a bugger on the first firing.

Then check a freshly full length sized case from your die, the same way. It could be a factory shell is within .004 in your chamber, but full length sizing with your die puts it to .006 or so. (Really this is the measurement that matters since your reloading.)

This is cool. So I put a piece of masking tape that measures 0.005” on the case head. I cut out a .308 caliber circle with a spare 30-06 case and used that as my circle, so it doesn’t go all the way to the edge of the case head but it covers most of it. Bolt closed fine. Added a piece. Still closed. Added another and it was quite a stiff closing. I peeled the stack of tape off and measured it again and it was 0.013”.

I was worried about masking tape being compressible so I reran the experiment with clear packing tape that measured 0.003”. After two layers it was a little stiffer but not bad. After three layers the bolt was very stiff, but I could have forced it closed. That stack measured 0.0115” after I peeled it off.

My dental pick is too awkward to feel the chamber and I can’t for the life of me find a paper clip but that’s next on my troubleshooting list.



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I'm not there to verify but if you're accurately reporting your measurments, that's too much. Actually outside of saami maximum of .010. Tape will slightly compress, but I find it gets you real close. For example that old 8x57 mauser sporter would not begin to close with ONE piece of .004 tape and I can full length size with very little case stretch after firing. But I don't force it shut, you should feel it get tight......that means you're against.

My Springfield would close on two .002 pieces, but caused resistance right at the end with three .002 pieces. I had a gun smith double check it and he had a .005 metal shim he put behind a go gauge, and it got tight right before full closing, so my tape method was within .001.


The best way to get a good feel is to strip your bolt so there's no firing pin, spring, and cocking piece in it. The bolt will flop shut by itself. You will immediately feel when you have enough tape that any gap between the case shoulder and the bolt face is removed.

 

[hunter24605]

By some chance do you use a Lee Quick Trim? I see those lines on some of my brass that I have a Lee Quick Trim die for..Sometimes while trimming the brass it will spin in the die and leave those uniform scratches.

 

[cloverleaf]

https://i.postimg.cc/MGV5L1bR/IMG-1122.jpg

I do not think you are looking at imminent separation. But there are more experienced opinions than mine above. So my opinion is FWIW (and maybe not much). In the photo above you can see a line just above the belt on the cases. I had to try them and you see what happens. Maybe I don't have the touch but I never felt I learned much from the paper clip test. You could cut open one of the cases in the photo, clean it up and see what you find. In the long run, you will learn about your rifle, and to me that's worth loosing a case. Just my .02. CL

 

[gbflyer]

The rifle is a stock Winchester Model 70 in .280 Rem. I haven’t bumped the shoulder and only full sized them for the first firing. I don’t keep strict record of how many firings the bass has so <5 is an educated guess. It’s absolutely in the single digits. The mark goes all the way around. I have never checked head space but I take it need to buy some gauges?

I rubbed a dental pick on the inside of the case and didn’t feel anything so that part has me confused as well.


Sent from my iPhone using Tapatalk

Over 1 but not able to close on two .004 pieces, the gun is still safe but brass would stretch like a bugger on the first firing.

Then check a freshly full length sized case from your die, the same way. It could be a factory shell is within .004 in your chamber, but full length sizing with your die puts it to .006 or so. (Really this is the measurement that matters since your reloading.)

This is cool. So I put a piece of masking tape that measures 0.005” on the case head. I cut out a .308 caliber circle with a spare 30-06 case and used that as my circle, so it doesn’t go all the way to the edge of the case head but it covers most of it. Bolt closed fine. Added a piece. Still closed. Added another and it was quite a stiff closing. I peeled the stack of tape off and measured it again and it was 0.013”.

I was worried about masking tape being compressible so I reran the experiment with clear packing tape that measured 0.003”. After two layers it was a little stiffer but not bad. After three layers the bolt was very stiff, but I could have forced it closed. That stack measured 0.0115” after I peeled it off.

My dental pick is too awkward to feel the chamber and I can’t for the life of me find a paper clip but that’s next on my troubleshooting list.



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I'm not there to verify but if you're accurately reporting your measurments, that's too much. Actually outside of saami maximum of .010. Tape will slightly compress, but I find it gets you real close. For example that old 8x57 mauser sporter would not begin to close with ONE piece of .004 tape and I can full length size with very little case stretch after firing. But I don't force it shut, you should feel it get tight......that means you're against.

My Springfield would close on two .002 pieces, but caused resistance right at the end with three .002 pieces. I had a gun smith double check it and he had a .005 metal shim he put behind a go gauge, and it got tight right before full closing, so my tape method was within .001.


The best way to get a good feel is to strip your bolt so there's no firing pin, spring, and cocking piece in it. The bolt will flop shut by itself. You will immediately feel when you have enough tape that any gap between the case shoulder and the bolt face is removed.

Not to be disagreeable but a new cartridge is not the way to determine excessive headspace on a cartridge that headspace’s on the shoulder as the OP’s does. It’s not at all uncommon for a new case to be significantly undersized, up to .010 or more and very random to boot. Get a go - gauge and put your tape on that. I have headspaced on a new cartridge that is for something belted, but I set them up with .002-.003 clearance.

 

[ShadeTree]

Gbflyer, You're not being disagreeable and not wrong, there is variances, but a factory cartridge should not be so far below a possible maximum chamber dimension that it would be pushing the line, or over the line of dangerous. You might not end up with an exact measurement, but it will point out an obvious problem or 1 to be suspicious of.


I check every gun just to know how tight or sloppy I'm dealing with prior to loading and shooting the first time so I'm not surprised with a problem I had no clue about. Most times it's an exercise in needless safety check as they are gonna be good and snug, but I have 1 gun that is on the long side of .010 and over, every way I checked it.....that one I create a false shoulder for on the first firing to give the case support, then load just bumping the shoulders like normal after that.

 

[ShadeTree]

I also agree with several on here that are thinking it's possibly a scratch......doesn't quite look right for separation, including it's a little far down the case, but it doesn't take long to be safe and check to be sure.

 

[fightthenoise]

I also agree with several on here that are thinking it's possibly a scratch......doesn't quite look right for separation, including it's a little far down the case, but it doesn't take long to be safe and check to be sure.

Agreed. Also for the record I did all my measurements above on a full length sized case because I don’t keep any factory ammo on hand. Could the die reflect the excess head space or is it definitely the chamber? I was thinking of just buying a no-go gauge but it’s such a one time tool for a caliber I only plan to have one of.


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